Motion-converting device



Sept. 12, 1961 R. H. wlsE 2,999,399

MOTION-CONVERTING DEVICE Filed May 2, 1957 4 Sheets-Sheet 1 INVENTOR.

RALPH H. WISE RQAMIQ A TTORNEYS Sept. 12, 1961 R. H. WISE MOTION-CONVERTING DEVICE 4 Sheets-Sheet 2 Filed May 2, 1957 INVENTOR PAL PH H. W/s E ATTORNEYS 4 Sheets-Sheet 3 AT 3 a R. H. WISE MOTION-CONVERTING DEVICE a3 aza 236 8 83 Sept. 12, 1961 Filed May 2, 1957 lllllll INVENTOR. RALPH H. WISE ATTORNEYS ZIS ZIZ

Sept. 12, 1961 R. H. WISE 2,999,399

MOTION-CONVERTING DEVICE Filed May 2, 1957 4 Sheets-Sheet 4 INVENTOR. RALPH H. WISE ATTORNEYS United States Patent 2,999,399 MOTION-CONVERTING DEVICE Ralph H. Wise, Gary, Ind., assignor, by mesne assignments, to The Anderson Company, a corporation of Indiana Filed May 2, 1957, Ser. No. 656,587 Claims. (Cl. 74-441) This invention relates to a motion-converting device and more particularly to an adjustable means for removing slack from between operative elements of a motion converting device.

Prior to the instant invention a great deal of difficulty was encountered in designing and successfully operating a substantially trouble-free nut and thread motion-converting mechanism for use in combination with a rotatable shaft of an electric motor. That is to say, no known mechanism of this type is currently on the market which has been designed to operate with a conventionally sized motor and rotating drive shaft that has been adapted to be drivingly connected to a reciprocating driven member, that is eflicient and successfully operative.

Motion-converting devices have frequently been employed as a mechanical movement for effecting a change from a rotating motion to a linear motion, while providing either an increase or decrease in the amount of force available therefrom. This type of device has particular application when used in conjunction with an electric motor wherein it is desired to change the rotating motion of the drive shaft to a linear, reciprocating motion of a driven element. In order to design a driven element having a sutficiently long linear stroke, in one of the forms of the invention here shown, it has been found desirable that said driven element pass axially through a hollow drive shaft of a reversible motor whereupon almost any length of driven element can be used within reasonable limits. According to known prior art practices, to accomplish this axial linear movement of a driven element through the drive shaft of an electric motor, generally a redesign of the whole motor was required. However, in the instant invention, it is contemplated that the standard diameter of the drive shaft be maintained, the only change required being to the bearing mounting of said shaft relative to the motor housing to accommodate the larger radial and axial thrust loads placed thereon by the driven element.

In another form of the invention, a simple pulley drive arrangement may be used. The device of this invention will be found to be adaptable to most any form of thread and nut drive arrangement, the invention being concerned primarily with the combination of the nut and thread means.

Thus, in the hollow shaft adaptation of the invention, to convert the oppositely directed rotating motions of the drive shaft of a reversible motor to the oppositely directed linear motions of the driven member, an exteriorly positioned motion-converting assembly is rigidly mounted on the drive shaft in operative engagement with a nonrotating axially movable driven element whereby operation of the motor will result in linear movement. of the driven element; The motion converting assembly shown in the instant drawings contemplates the use of two nut means connected in tandem relationship or spaced axially along a screw member. The nuts can be generally of the type shown and described in my copending application Serial No. 585,651 filed May 18, 1956, now Patent No. 2,966,071. With the nuts assembled in tandem relationship, certain problems arise with respect to looseness or play between the successive nuts and the screw, which results in lost-motion, which of course is undesirable usually, and in any event produces needless wear on the tion-conversion between the motor and the screw.

The present invention incorporates not only the features of an inexpensive, eflicient means for converting the rotating motion of a conventional reversible motor to the linear motion of a driven screw member, but also the features of a novel adjustment means for substantially eliminating the looseness or play which might otherwise be present in the motion-converting assembly operatively associated between a driving member and the driven screw member.

With these various advantages in view, the invention comprises the novel features of construction and the novel manner of combining and arranging the same, all of which will be fully described hereinafter and particularly pointed out in the appended claims.

In the drawings:

FIGURE 1 is a cross-sectional side elevation of an elec tric motor and motion-converting device illustrating one manner of making use of my invention;

FIGURE 2 is a sectional view taken along the line 22 of FIGURE 1;

FIGURE 3 is an elevational sectional view taken along the line 33 of FIGURE 1;

FIGURE 4 is a cross-sectional view taken along line 4-4 of FIGURE 1;

FIGURE 5 is a cross-sectional view taken along line 5-5 of FIGURE 1;

FIGURE 6 is a cross-sectional view taken along line 6-6 of FIGURE 1;

FIGURE 7 is a cross-sectional view taken along line 77 of FIGURE 1;

FIGURE 8 is a cross-sectional view partly broken away taken along the line 8-8 in FIGURE 1;

FIGURE 9 is a cross-sectional side elevation of a modified form of my motion-converting device; and

FIGURE 10 is an end elevation partially in section of the modified form of my invention illustrated in FIG- URE 9.

Referring to the drawings wherein similar reference numerals refer to similar parts throughout the several views, FIGURES 18 illustrate one form of my invention wherein 10 designates a reversible electric motor having an outer casing or housing 12, a rotor 14, and a plurality of energizing coils 16 which when properly energized by a particular setting of a switch 17, see FIGURE 8, will drive said rotor in either a clockwise or counterclockwise direction in a conventional manner. A pair of bellshaped mountings 18, 20 are integrally formed with said housing 12 in the axial face portions thereof and have the apex of each bell inwardly disposed with respect to said housing 12. The apex portion of each bell is apertured for receiving therein the hollow drive shaft or sleeve 22. Said hollow sleeve 22 is rigidly attached to the rotor 14 by the lock rings 24 and key 25 and is journalled in said housing by bearings 26 and 28 supported in said mountings 18 and 20.

The bearing 26 on one end portion of the sleeve 22 is designed for transmitting radial thrust only and comprises a pair of closely spaced peripheral grooves 30, 31 separated by a ridge 32 formed in the outer surface of the sleeve 22. Seated in these grooves are the toroidal surfaces of each of a plurality of peripherally spaced hearing members 34 which are adapted to transmit the entire radial load imposed upon the shaft 22 at this point. A carrier member 36 has formed near one end portion a plurality of rectangularly-shaped apertures 38 in each one of which is seated one of said bearing members 34. The carrier member 36 has an extended portion 39 which projects beyond the exterior portion of the motor housing 12 and has an axially disposed bore 40 for receiving a screw member 41 which will be described more in detail hereinafter. A cylindrical insert 42 is positioned between the bearing-members 34, carrier 36, and the surface of the bore forming a bearing surface for retaining said. bearing elements in position relative to the sleeve 22. An upstanding collar 44 is formed around the outer periphery of said insert 42, the collar being adapted to bear against a protruding portion of the aperture formed in the bell 18 for holding said insert 42 in assembled position in the motor.

The other end portion of the motor housing has the large bearing 28 nested between the bell 20 and a pair of grooves 46, 47 in the outer periphery of the sleeve 22 so as to accommodate both axial and radial thrust loads. To accommodate the compound radial and axial thrust loads, a boring ring 49 having an internal seat 50 isnested in a recess 51 formed in the edge of the aperture in, the bell 20. One toroidal surface of each of a plurality of multi-surfaced bearing members 53 bears against said internal seat 50 while the diametrically opposite toroidal surfaces of the bearing members 53 seat in said pair of grooves 46, 47 in the periphery of the sleeve 22. The bearing members 53 are held against substantial axial movement and in equally spaced relation with respect toeach other by means of a carrier 55 which has a plurality of rectangularly-shaped apertures for receiving the bearing members 53. A flared retaining sleeve 57 is pressed within the mouth of the bell 20 and has an internal seat 58 in rolling engagement with a dififerent toroidal surface of the bearing members 53 so as to permit said bearing members to roll relative to the. housing. A snap ring 59 is seated in an internal groove in the mouth of the bell 20 for holding the bearing 28 assembled on the sleeve 22. With the construction shown and described, it will be obvious that the sleeve 22 is supported first against radial thrust only by bearing 26 since bearing members 34 are supported for rolling engagement between the grooves 30 and 31 on sleeve 22 and insert 42 carried by housing 12, and second against radial and axial thrust by bearing 28 wherein the bearing members 53 cooperate with grooves 46 and 47 and are constrained to. engage the seats 50 and 58 for transmitting any axial thrust to housing 12 through bell mounting 2d.

The end portion 60 of the sleeve 22 nearest the bearing 28' is flared outwardly so as to provide a seating surface 61 for a cylindrically-shaped extension 62 which is adapted to have a conical neck to cooperate with said flared end portion of the sleeve, the extension being keyed to shaft 22 and positioned axially therein between seat 61 and the retaining ring 64 which seats in a groove in the surface of the sleeve. Said cylindrical extension 62 has a radially extending driving flange or ring 65 which has a plurality of equally spaced oppositely disposed pairs of arcuate slots designated as 66 and 67 formed therein, as best illustrated in FIGURE 6.

A pair of identically constructed motion-transmitting nuts 70, as more fully described in the above-referred-to copending application, are operatively connected in tandem relationship axially of each other along the screw 41 and are adjustably connected to the flange 65 and to each other. Each of said nuts 70 has a pair of radially disposed attaching arms 71 which have apertures 72 there.- through. The apertures 72 in one nut 70 areada'pted to be substantially aligned with one pair of slots 66 while the apertures 72 in the other nut 70 are adapted to be substantially aligned with the slots 67. The central portion 74 of each nut 70 has a pair of opposed, cup-shaped elements 75 which have aligned apertures 76 for receiving a bearing sleeve or carrier 77 therethrough. As best illustrated in FIGURES 1 and 6, three rectangular slots 78 are equidistantly spaced apart in said sleeve 77 with the major axis of each slot being substantially parallel to the longitudinal axis of the sleeve 77. Positionedin' each slot 78 is abearing member 80 provided with, a plurality of concentrically disposed enlarged portions having, toroidal surfaces 81, the enlarged portions being spaced apart along the axis thereof. The end pair of toroidal;

surfaces 81 of each bearing member are adapted to be engaged between the shoulders 83 in each nut 70, the sides of the threads 84 on the screw 41 so as to transmit axial thrust from the sleeve 22 to the screw 41, and the bearing surface 85 in the nuts 70 so as to transmit radial and axial thrust between the nut 70 and the screw 41. In this manner, the threaded shaft is bothsupported and driven as the nut is rotated.

Two such nuts as above described are carried at the end of shaft 41 and these motion-transmitting nuts 70 are held in spaced apart relation by means of a spacer member which is composed of two concentrically disposed cylindrical members 89 and 90 adapted to be relatively fixed together by means. of the straps 91 fastened in radially directed countersunk grooves 92 in the opposite. ends of the members 89, 90. The inner sleeve or member 90 has both ends chamfered, indicated as 93, on the inner peripheral edge portions such that as the spacer member is assembled on the first nut 70 the chamfering 93 will guide the spacer into position over the cup-shaped element 75 of the nut 70. The inner diameter of the spacer member is substantially the same as the outer diameter of the cup-shaped element 75 of the two motion-transmitting nuts 70 so that when the nuts are assembled, as shown in FIGURE 1, the spacer member will grip said element 75 sufficiently to substantially support the two nuts in axial alignment and yet permit limited relative axial adjustment of the two nuts along the shaft 41, for a purpose that will appear more fully below.

A pair of elongated bolts 95 pass through the one pair of arcuate slots 66 in the driving flange 65 that is supported on drive shaft 22, and the bolts 72 also pass through apertures 72 in the attaching arms 71 of the first nut 79. The bolts are of sufficient length to extend through the space 96 between the concentric cylindrical members 89, 90 which form the spacer member and are adjustably mounted relative to the spacer by nuts 97 and washers 97 that are supported byed'gewise engagement with radial straps 91 and the ends of spacers 89 and 90 whereby tightening of said nuts 97 will secure the first motiont-ransmitting nut 70 in a desired fixed position relative to the flange 65. The second motion-transmitting nut 70 has a pair of elongated bolts 98' passing through its attaching arms 71, to extend through space 96- between the cylindrical sleeves 89, 90 in the spacer member and through the pair of aligned arcuate slots 67 in the flange 65. The bolts 98 are fixedly mounted thereon by means of nuts 99 whereby tightening of said nuts 99 on said bolts 98 will secure said second motion-transmitting nut in a fixed position relative to said flange 65 on said sleeve 22.

By loosening either one or both pairs of the nuts 97 and 99, it is possible to rotate either one or both of the motion-transmitting nuts 70 on shaft 41 in either direction as far as the arcuate slots 66, 67 will permit, for a laterto-be-descri'bed reason. As the nuts 70 are thus rotated, it is apparent that they may be caused to move relative to each other axially of the shaft 41' and shoulders 75 of one or the other of the nuts 70 must slide axially within the bore of spacer element 90.

As will be obvious, it is almost impossible to so con struct the motion-transmitting nuts 70 to such precise tolerances as to eliminate play therebetween when they are assembled in spaced apart relation along the screw '41. However, according to the instant invention, by loosening two of the threaded nuts 99 on the bolts 98, passing through the arcuate slots 67 in the flange 65, it is possible to rotate the second motion-transmitting nut 70 relative to the first motion-transmitting nut 7 t in either a clockwise or counterclockwise direction through any distance up to the length of the arc of the slots 67, whereby any slack or play existing between the motlontransmitting nutsv 70 can be taken up by-moving the bearing members, 80 in the second motionrtransmittingnut- 7-9 in either an advancing or retracting direction along the threads of the screw 41 until the desired axial spacing between the toroidal surfaces 81 of the second nut 70 and the toroidal surfaces 81 of the first nut 70 is obtained whereby substantially all undue friction or binding as well as all play or slack may be eliminated between the nuts 70 and threaded shaft 41.

When the driven screw 41 is mounted vertically, it may sometimes become necessary to provide a means for preventing the motor and the work load carried by the screw 41 from free-wheeling relative to each other. For this reason a one-way braking device, indicated generally by the numeral 105, may be provided which is illustrated in detail in FIGURES 1 an 8. The brake 105 is adapted to be supported on the relatively fixed motor housing 12 in a manner to cooperate with the extension 62 that is keyed to the sleeve 22. For this purpose the sleeve has a collar 106 fixed thereto, having an upstanding rib 107 for holding said brake onto said collar 106 on one side and with a snap ring 108 engaging in a groove in the collar 106 for holding the brake on said collar on the other side. The brake 105 comprises a supporting ring 110 having an aperture 112 therethrough for loosely surrounding said collar 106 and having an offset integral arm 114 adapted to be rigidly fastened to the motor housing 12 such that the collar 106 and sleeve 22 are free to rotate within the aperture 112. Embracing a portion of said ring 110 is a bifurcated J-shaped member 115 which is pivotally connected to said ring 110 by pin 116, such that the two arms 117 and 118, which form the loop portion of the J of said bifurcated member 115, embrace the opposite sides of the ring 110 and a continuation 119 thereof which forms the stem portion of the J extends generally tangentially outwardly from the surface of the collar 106 for operative engagement with a core 120 of an electric solenoid 121. The free end of the loop portion of the J extends beyond the pivot pin 116 and has an extending portion 123 which has a notch 124 therein for receiving one end of a coil tension spring 126, the other end of which engages in a seat 127 formed in the ring 110. The extending portion 123 of the member 115 also has a cam-like element 129 extending downwardly from the pivot pin 116 referring to the view shown in FIGURE 8, the cam being such that when the solenoid 121 is de-energized the spring 126 will pivot the bifurcated member 115 about the pin 116 so as to engage said earn 129 with the surface of the collar 106 to become wedged between pin 116 and the surface of collar 106 thereby preventing rotation of the collar and drive 22 in a counterclockwise direction. Since the cam does not wedge against or grip against any portion of the collar during clockwise rotation of the sleeve 22, the sleeve will be free at all times to rotate in that direction.

When the electric current is turned on to the motor 10, the solenoid 121 will be energized and the solenoid is operative to move the core 120 to the left as viewed in FIGURE 8 which will pivot the bifurcated member 115 in a clockwise direction about the pivot pin 116 and raise the cam 129 out of engagement with the collar 106 whereupon the sleeve 22 will be free to rotate in either a clockwise or counterclockwise direction. When the current to the electric motor is shut OK, the electric motor and solenoid will be de-energized and the spring 126 will pivot the bifuracted member in a counterclockwise direction as viewed in FIGURE 8 to cause cam 129 to move into braking position with respect to the collar 106 as above described.

A source of electrical power is introduced to the motor 10 by wire 135, which is divided into two leads 136, 137. Lead 136 is connected to the movable element or blade 138 of the switch 17, which has two contact ends 140, 141, that are adapted to selectively contact one terminal of each pair of terminals 143, 144 or 145, 146. Lead 137 is divided into two parts, one part 148 going to the motor 10 and the other part .149 going through the solenoid 121 to a jumper bar 150 which connects the pair of terminals 143, 144. Terminal 145 of the switch, is connected through lead 152 with a specific set of coils 16 in the motor in such a way as to produce clockwise rotation of the motor when contacted by the end 141 of the switch blade 138 and theother terminal 146 of the switch is connected by lead .153 with a different set of coils, 16 in the motor to produce counterclockwise rotation of the motor when contacted by end 141 of the switch blade 138.

With the switch 17 in the off position illustrated in FIGURE 8, the motor and solenoid are de-energized so that the brake is activated by the spring 126 so as to cause cam 129 to lockthe sleeve 22 against clockwise rotation referring to FIGURE 8. Rotating the switch 17 in either direction will energize the solenoid 121 and release the brake 105 and when it is rotated clockwise, current will pass through solenoid 121, switch 17 to terminal 145 whereupon the motor will be driven in a clockwise direction. Flipping the switch 17 in a counterclockwise direction will also effect a release of the brake 105 by energizing the solenoid 121 and with this setting of the switch current will pass through solenoid 121, switch 17, and through terminal 146 to the motor for driving the motor in a counterclockwise direction.

In operation, a work load is attached to either one or both ends of the non-rotatable, linearly reciprocable screw 41 such that movement of the screw will produce useful work at the output of the motion-converting means. The motor 10 is preferably rigidly mounted against axial movement whereby it is driven to reciprocate the screw 41. However, it is contemplated that the reverse of this situation is to be included within the scope of this invention, namely the rigid fixing of the screw against axial and rotational movement and translating, but not rotating, the motor housing .12 along the axis of the screw for performing the intended useful work.

With the work loads disposed for axial movement, the motion-transmitting device is adjusted by the relative turning of nuts 70 on shaft 41, for removing play between the motor 10 and the screw 41 and the nuts are then fixed in the desired positions. The motor may then be energized to effect a drive in one direction, and in the preferred device, will drive the shaft to the right, for example, as viewed in FIGURE 1 and energization of the motor to drive it in the opposite direction will drive the shaft to the left. After repeated use of the device, a certain degree of play may develope as the parts wear in, and if such an event should occur, the mere loosening of one or the other pair of threaded nuts 97 or 99 on the bolts 95 or 98, respectively, will permit one motion-transmitting nut 70 to be rotated clockwise or counterclockwise relative to the other motion-transmitting nut 7 0 until once again the slack is removed therebetween. The nuts are then tightened down and the device is once again made operative in an efl'icient manner.

It is abvious that more than two motion-transmitting nuts may be assembled in adjustable tandem relationship along the axis of the screw by inserting additional spacer members 87 between successive motion-transmitting nut for distributing the loads in a greater number of increments between the motor and the screw without departing from the spirit of this invention, each successive motion-transmitting nut 70 being cumulative when its action is combined with the action of the already joined motion-transmitting nuts 70 shown and described'above.

The form of my invention shown in FIGURES 9 and 10 illustrates a modification wherein the driven screw 41 is mounted to reciprocate along an axis whichlies substantially parallel to, but is not coincident with, the axis of the drive shaft 222 of the reversible motor 210. A double seated pulley 212 is locked on the shaft 222 by set screw 214 such that rotation of the drive shaft will be transmitted to a pair of belts 216, 217 through said pulley 212. The belts 216, 217 engage with-a larger pulley 219 which is locked to the outer surface of the spacer member composed of elements 89 and 90, by means of screw 220 whereby rotational motion of the motor will be transmitted to. the motion-transmitting nuts 70 for rotating same about the axis of the screw 41. The relationship between the nuts 70, the spacer member and the screw 41 is the same in thisform of my invention as in the form shown in FIGURES 1-8 so a description thereof will not be repeated here. Briefly, it should be noted, however, that each extending arm 71 of the nuts 70 has an arcuate slot 223 formed'therein about the axis of the nut 70. A pair of. bolts 225, which pass through the space provided between the outer and inner portions 89 and 90 of the spacer member and through. the arcuate slots 223, are threaded into the circular bearing plate or attaching member 226 for supporting and locking the motion-transmitting nuts 70. In this form of the device, each of the nuts is mounted on plate. 226 in adjusted position relative to other nut 70 andto the bearing plate 226. An identical pair of bolts 227 may be threaded through the arcuate slots 223 in the arms 71 of the nut 7.0 located on the left in FIGURE 9, then through the spacer member 87 and into the bearing plate 226 for permitting adjustment of the left-hand nut 70 relative to the right-hand nut 70 and relative to the bearing plate 226. From the above-described relationship, it can be seen that the two nuts 70 can be adiusted relative to each other along the threaded member 41 by loosening either or both pairs of bolts 225 or 227 and rotating one nut 70 relative to the other whereupon tightening the bolts locks the nuts on the bearing plate 226 for further use.

p The nuts 7t) and bearing plate 226 are supported in substantially friction free relationship with respect to a stationary mounting bracket 229 by means of the plurality of bearings 230 equidistantly spaced about the circular periphery of the plate 226 by a carrier 232. The bearings 230 are. seated between a pair of grooves 234 in the periphery of the. plate 226 and a pair of shoulders 235 formed in the inner surface of a pair of bearing rings 236. A flanged retainer 238 is assembled around the one side face of one of the rings and the outer surface of both of the rings 236 and is adapted to be fastened to the support member 229 carried on any appropriate base, not shown. The support. 22? may be apertured at the center to permit the screw 41 to pass therethrough and is adapted to hold the bearing. rings 236 and carrier 232 assembled in the retainer 238 which positions the bearings 230 to receive the axial and radial thrust loads from the motor to the screw 41.

' A braking device 105, substantially the same as that. shown and described above, is mounted on the shaft 222 so as to prevent free-wheeling of the device in one direction when the. motor is de-activated. The brake functions in the same manner as previously described, that is, by means of the cam 129 engaging the shaft to prevent rotation in one direction when the motor 10 is not energized.

The modifications of my invention as illustrated in FIG- URES 1-8 and FIGURES 9 and 10 are used to transform rotary motion. to linear motion with means for adjusting the motion-converting means relative to the screw to reduce the amount of play or slack therebetween.

Many other applications of the present invention may be apparent to those skilled in the art, it being understood that the applications of the invention shown in the draw ings are by way of illustration and not by way of limitation.

- I claim: 7

1. A motion transmitting mechanism comprising means for rotatably driving a hollow sleeve, an axially extending nonrotatable screw means passing through the. hollow portion of the sleeve, a plurality of axially spaced motion-transmitting. members carried by said hollow sleeve, a carrier, surrounding the screw and positioned within each motion-transmitting member, bearing means carried by the carrier and engaging the screw and the motion-transmitting member for transmitting rotating motion of the sleeve to linear motion of the screw, and means for rotatively adjusting one of said motion-transmitting members relative to the other motion-transmitting member whereby slack is removed from between the motion-transmitting members and the screw means.

2. A motion-converting mechanism comprising motor means, motion-transmitting means rotatably driven by said. motor means, nonrotatable screw means passing through said motion-transmitting means and operatively engaged thereby and means for axially adjusting portions of said motion-transmitting means relative to each other comprising attaching means adapted to rotate with said motion-transmitting means and having a plurality of apertures therethrough, outwardly extending arms carried by each portion of said motion-transmitting means and. having apertures. therethrough adapted to be aligned. with at least two of the apertures in the attaching means, the apertures in said extending arms or said attaching. means being arcuate in shape, spacer means positioned between said portions of the motion-transmitting means for axially spacing said portions, and fastening means for securing said spacer means and one of said portions of the motion-transmitting means to the attaching means whereby the slack may be removed from between the motion-transmitting means and the screw means.

3. A motion-transmitting mechanism comprising a reversible motor, a hollow sleeve extending through said motor and rotatably driven thereby, an axially extending nonrotatable screw means passing through the hollow portion of the sleeve, a pair of axially spaced motiontransmitting members carried by said hollow sleeve and operatively engaging with said screw means, means for axially adjusting one of said motion-transmitting members relative to the other comprising a radially directed flange formed on said sleeve in slidable engagement with one of said motion-transmitting members, means for spacing said other motion-transmitting member from said first-mentioned member, bolt means passing through said spacing means for securing said first motion-transmitting member to said flange, additional bolt means. passing through said second motion-transmitting member and said spacing means for securing said second motion-trans mitting member to said flange, and means on both of said bolt means for selectively loosening said two motiontransmitting members relative to each other and to said flange whereby turning one member relative to the other will remove slack between the members and the screw.

4. In combination, a nonrotatable screw having a concentric helical groove therein, an elongate sleeve surrounding a portion of the screw and having means carried by one end portion for supporting a portion of said screw, a reversible electric motor operatively connected with said sleeve to effect rotation thereof in either a clockwise or counterclockwise direction, bearing means disposed between said sleeve and the casing of said motor for supporting said sleeve against axial and radial thrust loads, a laterally disposed flange rigidly carried by the other end portionof the sleeve exteriorly of the motor, means engaging with said sleeve for selectively preventing rotation. of said sleeve in either direction, a plurality of equally spaced arcuate slots formed in said flange, a motiontransmitting nut operatively engaged with said screw member, radially extending attaching means formed on said nut and having apertures therethrough adapted to be aligned with at least two of said arcuate slots in said flange, a second motion-transmitting nut operatively engaged with said screw member in axially spaced relation with respect to said first nut, radially extending attaching means formed on said second nut and having apertures therethrough adapted to be aligned with at least two other of said arcuate. slots, a pair of concentrically disposed spacer members. positioned between said motion-trans.--

mitting nuts, the inner spacer member slidably engaging with parts of said nuts and being chamfered near the inner surface thereof in close proximity to said second nut to provide clearance for the attaching means of said second nut, means passing between said spacer members and through the aligned apertures in the first nut and the slots in the flange for holding said first nut assembled on the flange, and means passing through the attaching means of the second nut and between the spacer members and into the other aligned arcuate slots in the flange for hold ing said second nut assembled on the flange whereby said second nut can be adjusted rotatively of the shaft relative to the first nut by rotation of one nut relative to the other through the arc permitted by the arcuate slots in the flange.

5. A mechanical movement comprising, in combination, a screw member having a concentric helical groove in the peripheral surf-ace thereof, a rotatably driven sleeve surrounding a portion of the screw member and having means carried by one end portion for radially supporting said screw member, a laterally disposed flange rigidly carried by the other end portion of the sleeve, two pairs of equally spaced arcuate slots formed in said flange, a first motion-transmitting nut operatively engaged with said screw member, a pair of radially extending ears carried by said nut in sliding relation with said flange and having apertures therethrough in alignment with one pair of said arcuate slots, a second motion-transmitting nut operatively engaged with said screw member in spaced relation with respect to said first nut, a pair of radially disposed apertured ears on said second nut, a pair of concentrically disposed spacer members positioned between said motion-transmitting nuts, a pair of adjustable retaining bolts passing between said spacer members and through the aligned apertures in the first nut and the slots in the flange for holding said first nut assembled on the flange, and a second pair of adjustable retaining bolts passing through the apertured ears of the second motiontransmitting nut and between the spacer members and into the other pair of arcuate slots in the flange for holding said second nut assembled on the flange whereby said second nut can be adjusted rotatively of the shaft relative to the first nut by rotation of one nut relative to the other through the are permitted by the arcuate slots in the flange.

6. In combination, a nonrotatable screw having a concentric helical groove therein, an elongate sleeve surrounding a portion of the screw and having means carried by one end portion for supporting said screw, a reversible electric motor operatively connected with said sleeve to eflect rotation thereof in either a clockwise or counterclockwise direction, a laterally disposed flange rigidly carried by the other end portion of the sleeve exteriorly of the motor, means carried by said sleeve for preventing rotation of said sleeve in one direction when operative, a plurality of equally spaced arcuate slots formed in said flange, a motion-transmitting nut operatively engaged with said screw member, attaching means carried by said nut and having apertures therethrough adapted to be aligned with at least two of said arcuate slots in said flange, a second motion-transmitting nut operatively engaged with said screw member in axially spaced relation with respect to said first nut, attaching means carried by said second nut and having apertures therethrough adapted to be aligned with at least two other of said arcuate slots, a pair of concentrically disposed spacer members positioned between said motion-transmitting nuts, means passing between said spacer members and through the aligned apertures in the first nut and the slots in the flange for holding said first nut assembled on the flange, and means passing through the attaching means of the second nut and between the spacer members and into the other aligned arcuate slots in the flange for holding said second nut assembled on the flange whereby said second nut can be adjusted rotatively of the shaft rela- 10 tive to the first nut by rotation of one nut relative to the other through the are permitted by the arcuate slots in the flange.

7. A compound nut structure comprising an elongate threaded screw, at least a pair of spaced axially aligned nut units operatively engaging with the threads of said screw, spacer means between said units, a flat ring member having its axis aligned with that of said nut units and being in contact with a side wall portion of one of the. units, said ring being formed with a plurality of equally spaced arcuate apertures and each of said nut units being formed with bolt-receiving apertures, and releasable clamp bolts passing through said apertures of the ring and nut units to admit relative rotative adjustment of the nut units along the screw.

8. A motion-converting mechanism including a tubular sleeve, an elongate nonrotatable threaded screw passing through said sleeve, a flat ring concentric to and rigid with one end of said sleeve, the peripheral portion of said ring being formed with equally spaced arcuate apertures lying in a common circle, spaced aligned nut units operatively engaged with the threads of said screw, spacer means between said units, a sidewall portion of one of said units abutting said ring, and releasable fastening means passing through peripheral portions of said nut units and the apertures of said ring to admit relative rotative adjustment of said nut units along said screw.

9. A motion-converting mechanism including a tubular sleeve, an elongate nonrotatable screw passing through said sleeve, a flat ring concentric to and rigid with one end of said sleeve, the peripheral portion of said ring being formed with equally spaced arcuate apertures lying in a common circle, spaced aligned nut units, spacer means between said units, each nut unit including a casing formed of two cylindrical tubular sections each having a radially outwardly extending flange at one end, said flanges being secured in abutting relation, elongate roller thread-engaging elements within each nut unit operatively engaging with said screw, said flange portion of one of said units abutting said ring, and releasable fastening means passing through the flanges of said nut units and the apertures ofsaid ring to admit relative rotative adjustment of said nut units along said screw.

10. A motion-converting mechanism including a tubular sleeve, an elongate screw passing through said sleeve,

a flat ring concentric to and rigid with one end of said sleeve, the peripheral portion of said ring being formed with equally spaced arcuate apertures, spaced aligned nut units, spacer means between said units, said spacer means including spaced concentric cylindrical tubular sections, each nut unit including a housing formed of two cylindrical tubular sections each having a radially outwardly extending flange at one end, said flanges being secured in abutting relation, roller thread-engaging elements within each nut unit operatively engaging with said screw, one housing section of each nut unit being telescoped within opposite ends of the inner section of said spacer means, the flange portion of one of said nut units abutting said ring, and releasable fastening means passing through portions of said nut units and the apertures of said ring to admit relative rotative adjustment of said nut units along said screw.

References Cited in the file of this patent UNITED STATES PATENTS 525,771 Parks Sept. 11, 1894 697,332 Doney Apr. 8, 1902 845,379 Thomas et al. Feb. 26, 1907 1,707,442 Maag Apr. 2, 1929 2,345,194 Grandberg et al Mar. 28, 1944 2,446,393 Russell Aug. 3, 1948 2,749,812 Wetzel June 12, 1956 FOREIGN PATENTS 1,062,878 France Apr. 28, 1954 

